Engineering News Fall 2014

No swimming, no diving ... no problem in parched lakebeds like Chesbro Reservoir in Morgan Hill, California.

Water, water, anywhere?

Heidi Williams

As the golden hills surrounding Santa Clara Valley crack and turn dusty brown in the driest year on record for many parts of the state, the subject of water is, naturally, on our minds here in California. According to Keith Schneider, senior editor of Circle of Blue, an independent, nonpartisan journalism organization, "The California drought, now in its third year and apparently deepening, may develop into the most significant test in American history of the capacity of residents, farmers, businesses and governments to ensure a state’s water security in the new era of climate change."

Edwin Maurer, associate professor of civil engineering and internationally renowned expert on climate change, agrees that this is a momentous time. Maurer explains that the ramp-up in heat resulting from global climate change makes droughts start earlier, last longer, and be more intense. "It’s a complex picture, but especially in the southwest, that is going to be the case," he said. Intertwined with other factors such as snow on the ground for less of the year and the incidence of more wildfires, soils are drying out more which leads to hotter air. All these factors deepen the drought, and they are all becoming more intensified. "Roughly every ten years we experience a drought in California," he continued. "In the past, we’ve looked at it as something we need to deal with 'this year.' We need to think more seriously now about planning for reduced availability of water in the long-term rather than going into drought-response mode and then backing out once the rain starts to fall. We need to change the infrastructure so we don’t panic every five to ten years.

"Recharging California’s groundwater and managing its use in a more conservative, concerted manner is an important step toward water solvency. "We use groundwater as a buffer when there is not enough surface water to serve our needs, but even in a wet year about forty percent of our water demand is satisfied by pumping it from our aquifers. Santa Clara Valley Water District does a good job of managing and monitoring its system, but in California’s Central Valley there is no one authority in charge—no one monitors how much is pumped or where the levels are. Proposed legislation is working its way through to address a process for groundwater management and that would be a huge help."

For now, Maurer said, the big payoff comes from conservation. In the agriculture sector, 30 to 50 percent could be cut back by converting to drip or sprinkler irrigation rather than flooding. And farmers are experimenting with "managed stress"—intentionally depriving plants of water in a calculated way to produce a stronger crop. In the urban sector, the largest water usage is residential, with landscaping accounting for the biggest chunk (we do love our lawns in California!). Changing our aesthetics to favor native vegetation and implementing standards to mandate dual plumbing to use reclaimed water for flushing toilets could go a long way toward a more sustainable future.

"I always stress in my classes that we shouldn't point our fingers at others," said Maurer. "We all have our own challenges based on our unique geography and climate. We need to look at what works and how to implement those things. There are tons of interesting approaches being taken and a lot of healthy dialogs are happening."